Right Ascension

Technically, the angular distance of a celestial object east of the
vernal equinox, measured in hours and minutes. Simply stated, one of the
two coordinates (declination is the other) that let you find celestial
objects by using a telescope's setting circles and a star chart or star
atlas. If you face the north celestial pole, the stars will rise
(ascend) on your right - hence the term "right ascension." The same
point on the 360 degree celestial sphere passes overhead every 24 hours,
making each hour of right ascension equal to 1/24th of a circle, or 15
degrees. Each degree of sky therefore moves past a stationary telescope
in four minutes - a rapid rate when observing at high power.